IR sensor sees mm grid on heatbed

Discussion in 'BigBox General Chat' started by W1EBR.Gene, Oct 26, 2016.

  1. W1EBR.Gene

    W1EBR.Gene Well-Known Member

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    I noticed that the IR height sensor "sees" the white grid lines on the heatbed. Putting a piece on black paper between the heatbed and the glass seems to have helped the IR sensor to more consistently register the bed location.

    Has anyone else noticed this?
     
  2. dc42

    dc42 Well-Known Member

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    I am not surprised. With transparent bed materials, the IR sensor works best when the reflection from behind the transparent bed is minimised. The white grid lines are reflecting too much. For best results, either use black paper as you have done, or choose your probe points to avoid the white lines.
     
  3. Paul Begley

    Paul Begley Well-Known Member

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    I've experienced similar.
    I've also wrapped some tape around the sensor/mount to reduce any ambient light
    Having recently tried blue masking tape, the head was homing about 3mm above the plate.
     
  4. W1EBR.Gene

    W1EBR.Gene Well-Known Member

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    Has anyone just used high temp flat black paint on the back side of the glass (or is it dumb to ruin one side of the glass which could get used if the other side gets scratched)?
     
  5. Spoon Unit

    Spoon Unit Well-Known Member

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    Because the z stop x,y coord is the same every time, why not just move it to the center of a grid point. Personally I've never had this problem. Possibly the UHU or Kapton tape I use on my glass reduces the problem...
     
  6. W1EBR.Gene

    W1EBR.Gene Well-Known Member

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    I was thinking about Mesh Bed Leveling with 9 measurement points...
     
  7. Spoon Unit

    Spoon Unit Well-Known Member

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    Yeh - I see. Still, with the UHU/Kapton, I've had zero issues with MBL. Completely predictable results, and perfect first layers in all four corners. Sorry that that doesn't really help.
     
  8. mike01hu

    mike01hu Well-Known Member

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    MBL does not use the IR sensor after the initial home and all the levelling data is referenced to that position and counting the microsteps, so painting the home point should be OK. It only needs to be a very small area.
     
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  9. Dr Jeep

    Dr Jeep Well-Known Member

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    If you don't want to paint one side of the glass and like me don't really benefit from the feature of that printed grid pattern...why not buy some black card from an art supplies shop and just place it between the glass and the PCB heater bed, that way both sides of the glass are useable still.
     
  10. eca

    eca Well-Known Member

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    Why not just use a black marker over the lines in that area?
     
  11. eca

    eca Well-Known Member

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    With my Duet it uses the IR for doing the different points instead of manually by hand, but I think I will try coloring over the white lines near the points to see if that helps get more consistent results.
     
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  12. mike01hu

    mike01hu Well-Known Member

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    Yes, I was referring to the Marlin MBL.:oops:
     
  13. eca

    eca Well-Known Member

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    Well, I think that the main point is that the IR sensor sees the white lines and can give different readings if it sees the lines. I know I will probably try coloring over the ones near the points that are measured to see if it makes a difference, especially with the Duet using it for bed leveling.
     
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